Current consumer electronics market is supplied with a variety of useful and small portable electronic devices that have become everyday carry items. Some notable examples of such devices are Bluetooth adapters, Universal Serial Bus (USB) flash drives, card readers, and WiFi adapters. These portable electronic devices typically include a core element provided in a housing, wherein the term “core element” as used herein refers mainly to a circuit board with a plug. The circuit board can be a flash memory module or a wireless communication module, but is not limited to the foregoing. The plug, on the other hand, can be a FireWire plug, an External Serial ATA (eSATA) plug, or a USB plug, to name only a few common plug standards. The plug is to be connected to a connector of an electronic apparatus, such as a laptop computer or a digital picture frame, so as to enable electrical connection and data transfer between the portable electronic device and the electronic apparatus.
A common mean of protecting the plug on the electronic device from damages when the device is not in use is to retract the plug into the housing. The mechanism disclosed in the prior art comprises a core element that can be moved to a retracted or extended position with a spring supported slide button. A main drawback of such mechanism is that the spring tends to fail due to material fatigue after repeated use. Another drawback of the mechanism is a strong friction between the housing and the carrier tray induced by the spring loaded slide button, which makes extension and retraction of the plug awkward, thus an exotic and more costly material, such as polyoxygenmethylene (POM) is preferably used to make the carrier tray. An improvement, as taught in the other prior art, uses a scotch yoke mechanism for retraction and extension of the plug. Please refer to FIG. 1 for a portable electronic device 1 having a rotary mechanism for plug extension and retraction. The core element 10 of the portable electronic device 1 is located in a housing 11, has a front end provided with a plug 100, and, as shown more clearly in FIG. 2, includes a circuit board 101. The portable electronic device 1 further includes a rail element 12, a sliding block 13, a crank 14, and a knob 15. The rail element 12 is connected to the core element 10. The sliding block 13 is engaged with the crank 14. The sliding block 13 is slidable in the slide rail of the rail element 12. The turning block 15 is inserted through the housing 11 and connected to the crank 14.
As shown in FIGS. 1 and 2, the plug 100 is extended from the housing 11 by rotating the knob 15, which in turn rotates the crank 14 about an axis defined by the knob 15 and drives the sliding block 13 to slide in the slide rail of the rail element 12. Consequently, the rail element 12 pushes the core element 10, and the plug 100 is moved out of the housing 11. When the knob 15 is turned in the opposite direction, the crank 14 is rotated therewith to drive the sliding block 13 and hence the rail element 12, thereby pulling the core element 10 inward; as a result, the plug 100 is moved into the housing 11. The mechanism effectively resolves the problems of a slide button type extension/retraction mechanism, but a major drawback of the portable electronic device 1 is that the knob 15 has to be rotated 180 degrees in order to fully extend the plug 100, which is rather burdensome to the users. Another drawback of the portable electronic device 1 is its complex structure and great number of components. Assembling these components requires a meticulous effort, and has to be done manually; using a lower cost automated process is not technically feasible. A further drawback caused by the large number of components is a greater susceptibility to errors or damage during assembly and consequently leads to a low yield rate. More importantly, the complicated structure prevents the conventional portable electronic device 1 from miniaturization, the volume of the device seldom meets user needs or design requirements.
Therefore, the present invention addresses the need for a plug extension/retraction mechanism that overcomes the various drawbacks of the prior arts, a mechanism that is user friendly, robust, easy to manufacture and cost effective.